[llvm] AMDGPU: Use ELF mangling in data layout (PR #163011)

[Alexis Engelke via llvm-commits]

aengelke wrote:

Clang still has the data layouts hard-coded in lib/Basic/Targets. In an ideal world we'd get rid of that first... some tests also include the data layout, I think that could be removed.

https://github.com/llvm/llvm-project/pull/163011